I've heard several demos of MQA (Master Quality Authenticated), the data-packing technology originally developed by Meridian that greatly reduces the bandwidth and storage requirements for digital audio while retaining all the fidelity of the master file from the studio that created it. However, all those demos have been MQA versus lossy MP3 versions of the same music. What I really wanted to hear was an A/B comparison of the original, uncompressed master file with an MQA-processed version played through an MQA-enabled DAC.

I finally got the opportunity to hear just such a demo at THE Show Newport last weekend. The files were played from a MacBook Air through a Meridian Explorer2 DAC ($300) with MQA decoding to a pair of Audeze LCD-2 headphones ($995), which, according to Audeze's specs, have frequency extension well beyond 20 kHz. All files were in FLAC format.

Admittedly, it was a sighted test—I selected what I heard at all times—so some readers will find my observations of questionable value. I agree that blind testing is the best way to make such comparisons, but the circumstances in this case did not allow for that, so this was the best I could do.

I started with a track called "Resonance" by percussionist Hiroshi Fukamizu, which starts with ambient cymbal sounds that have a lot of very high-frequency content. The unprocessed file was 24-bit/192 kHz at 5.022 Mbps (megabits per second), while the MQA file was 24/48 at 1.374 Mbps, and I could hear no difference between them at all.

Next was "Sultans of Swing" by Dire Straits; the unprocessed file was 24/192 at 5.066 Mbps, and the MQA file was 24/48 at 1.658 Mbps. Again, I could hear no difference between them.

I tried an old recording of "They Can't Take That Away From Me" by Ella Fitzgerald and Louis Armstrong; the unprocessed file was 24/96 at 2.363 Mbps, and the MQA file was 24/48 at 1.371 Mbps. The recording was relatively poor quality, and I thought Ella's voice was perhaps bit more mellow in the MQA track, but otherwise, it was very difficult to tell them apart.

Switching to classical music, I played a recording of Ravel's String Quartet in F Major, Assez vif, performed by the Guarneri Quartet. The unprocessed file was 24/192 at 5.017 Mbps, and the MQA file was 24/48 at 1.419 Mbps, and again, I could discern no difference at all.

Finally, I listened to the first movement of Mozart's Violin Concerto in D Major (KV218) performed by Marianne Thorsen and TrondheimSolistene, a wonderful recording by Morten Lindberg at 2L. In this case, the unprocessed file was 24/352.8 at 10.912 Mbps and the MQA file was 24/44.1 at 1.4 Mbps. With such a drastic reduction in bit rate, I thought this might be a real torture test, but as with the other modern recordings, I heard no difference at all.

Some audio reviewers claim that MQA-processed and decoded files actually sound better than the original master files because MQA reduces the "temporal blur" found in the upper harmonics of high-res digital recordings. I did not hear any improvement in this listening session. Still, it was remarkable to have heard no difference between the unprocessed and MQA files with a fifth to a tenth of the bit rate; this is akin to bringing uncompressed CD down to 256 or 128 kbps. Of course, there are other listening tests that can be performed, and I look forward to more of them in the future.